"Checking prerequisites for resizing Logical-Physical volume stack
The requested size change for the target disk or a related disk is too small. Please try a different disk or partition, or make a larger change.
Operation failed…"

Some screen shots would be helpful and also the size of your disk and the sizes you want to change the partitions to. Note that depending on how much data Boot Camp thinks Windows needs and how much space macOS is using the sizes you choose may not work and you may have to settle for sizes that are not optimal for your needs.
– Steve ChambersOct 12 '17 at 20:12